Deprecated the majority of all the testing assertions and replaced them with a much smaller core and access to all the collections the old assertions relied on. That way the regular test/unit assertions can be used against these. Added documentation about how to use it all.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@1189 5ecf4fe2-1ee6-0310-87b1-e25e094e27de